1. Field of the Invention
This invention relates to side pocket mandrels for use in oil wells and more particularly to an improved construction for side pocket mandrel and method of making the same.
2. Description of the Prior Art
Side pocket mandrels have in the past been connected to tubing strings and installed within the casing of a well for use in production of oil. These side pocket mandrels have an open bore through which tools can pass and an offset side pocket in which flow control devices (such as shown in U.S. Pat. No. 3,417,774) can be retrievably mounted by use of a latch device (such as shown in U.S. Pat. Nos. 3,741,601 and 3,827,493). As is well known in the industry, these mandrels typically have internal structure which cooperate with tools such as "kick over tools. " See, for example, my U.S. Pat. No. 3,876,001. These tools can be manipulated from the surface of the well to remove and install flow control devices in mandrels located down hole. There are a variety of constructions of such mandrels. Patents illustrating mandrel construction are included in the following list:
______________________________________ U.S. Pat. No. Inventor Issue Date ______________________________________ 2,824,525 McGowen, Jr. Feb. 25, 1958 2,948,341 Fredd Aug. 9, 1960 3,603,393 Terral et al Sept. 7, 1971 3,741,299 Terral June 26, 1973 3,796,259 Outhouse Mar. 12, 1974 3,807,499 Tausch et al Apr. 30, 1974 3,874,445 Terral Apr. 1, 1975 3,889,748 Tausch June 17, 1975 3,994,339 Goode et al Nov. 30, 1976 4,033,409 Hebert July 5, 1977 4,333,527 Higgins et al June 8, 1982 ______________________________________
Other mandrel constructions are shown in the patents referred to and cited in the above patents.
Many side pocket mandrels include a deflector structure (see for example, U.S. Pat. Nos. 3,741,299; 3,802,503 and 4,333,527). These deflectors can be positioned above the opening to the side pocket and receptacle bore. Deflectors have a ramp type upper surface to deflect larger tools into the main bore. These deflectors are normally spaced apart to allow seating of the flow control devices. These prior art deflectors have performed adequately to prevent larger tools from contacting the latch or entering the side pocket area. However, due to the spacing between the deflectors, smaller tools have, in some instances, entered the side pocket area and contacted the latch. In some instances, these smaller tools such as guides for coil tubing will hang on or wedge between the latch and side wall. Further downward jarring will bend the latch out into the open bore. This obstructs passage through the open bore and damages the latch. In some instances the latch can be broken off. These problems can result in expensive service work being required for the well.
In the construction of side pocket mandrels, it is sometimes necessary to spray the interior with a liquid or powdered coating material to form an ultra thin 6.003 to 0.012 inch) protective plastic coating. Coatings of this type are normally designed for coating tubing without internal protrusions. This coating is especially important in the exposed weld areas where the receptacle bore sub-assembly is welded to the mandrel body. In the past, the connection between the receptacle bore sub-assembly, deflectors and mandrel is such that spray coating of the welds is difficult or completely obstructed by the structure of the sub-assembly. See, for example the obstruction shown in FIGS. 3 of U.S. Pat. Nos. 3,741,299 and 3,603,393.
None of the prior art known to applicant includes a deflector structure which protects a latch from being bent out into the open bore or broken off by contact with smaller tools and none provides a mandrel structure which can be easily coated on the interior exposed welds.